I heated the large one in boiling water.

Then I brought the large stone near to the suspended small one.

Which immediately turned its flat side to the side B of the large

stone, and would cling to it.

I turned the ring, so as to present the side A of the large stone, to

the flat side of the small one.

The flat side was repelled, and the small stone, turning quick,

applied its high side to the side A of the large one.

This was precisely what ought to happen, on the supposition that the

flat side of the small stone, when heated in water, is positive, and

the high side negative; the side A of the large stone positive, and

the side B negative.

The effect was apparently the same as would have been produced, if

one magnet had been suspended by a thread, and the different poles of

another brought alternately near it.

I find that the face A, of the large stone, being coated with

leaf-gold (attached by the white of an egg, which will bear dipping

in hot water) becomes quicker and stronger in its effect on the cork

ball, repelling it the instant it comes in contact; which I suppose

to be occasioned by the united force of different parts of the face,

collected and acting together through the metal.

The Complete Works in Philosophy, Politics and Morals of the late Dr. Benjamin Franklin, Vol. 1 [of 3] · 第 197 / 291 题